psammite · Coastal Intelligence Office · Great South Bay
Old Inlet
The Fire Island Wilderness Breach — open Oct 2012 to ~2022 · live bay watch + the full measurement record
When Sandy tore an inlet through the Otis Pike Wilderness, two other breaches were closed within
weeks — this one, on federal land, was left open for a decade, then closed on its own. It became the bay's most
argued-over question: does the inlet drive the flooding? Below is the bay right now, the argument as
two people who live here actually had it, and the full measurement record of what the open decade did to the water.
The bay, right now · east Great South Bay at Watch Hill (by the old inlet)
Bay water level
…
reading the gauge…
Reading the waterAssembling the live picture of the bay…
The argument — Jan 12, 2024
The wind-setup case
A local boatman's read: on a sustained west (or strong south) wind the east end of the bay floods —
there's a name for it, and it works like storm surge. When the inlet flowed well it was a release valve,
and through that stretch there were zero floods; now it's closed and constricted, the water has nowhere to go.
His marina used to flood on a strong southerly and stopped as soon as the inlet opened.
The forcing case
The counter-read: before Sandy there wasn't nearly this much flooding and the inlet was closed —
Sandy blew it open, and now people blame it. More likely we're just seeing more storms, more water, more
wind, and more people in the way. The water goes where it's going to go.
What the record actually shows
Wind setup is real — a sustained westerly/southerly does stack water against the bay's lee shore, exactly as
described (that's the tile above turning warm when the wind lines up). But on the release-valve claim the monitoring
record sides with the forcing case: continuous tide gauges (USGS + Stony Brook) found the breach was
not measurably driving mainland flooding — the bad winters tracked a run of nor'easters and surge, in line
with the whole coast. Where the inlet did have a large, measured effect was water quality — the
record of that is below.
Then — what the open decade did to the water
Near the breach (east)
Control (west bay)
Breach open